This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application.
In wireless communication, different collections of communication protocols are available to provide different types of services and capabilities. High speed packet access (HSPA) is one of such collection of wireless communication protocols that extends and improves the performance of existing UMTS (universal mobile telecommunications system) protocols and is specified by different releases of the standard by the 3rd generation partnership project (3GPP) in the area of mobile network technology. The other non-limiting example wireless communication protocols are long term evolution (LTE), global system for mobile (GSM) and worldwide interoperability for microwave access (WiMax).
Multiple input multiple output (MIMO) transmission has been proposed and forms part of HSPA, LTE and WiMax) system standards. In single user multiple input multiple output (SU-MIMO), a MIMO receiver with multiple antennas and receiving circuitry receives the multiple streams, separates the multiple streams and determines the transmission symbols sent over each stream of the spatially multiplexed data streams.
The application of MIMO methods to wireless communication and in particular to HSPA systems such as the double-transmitter antenna array (D-TxAA) adopted by 3GPP enables a significant increase in data throughput and link range without additional bandwidth or transmit power requirements. These systems thus operate with a higher spectral efficiency (in other words, operate with a greater bits per second per Hertz of bandwidth) than conventional HSPA implementations and also have a higher link reliability or diversity (in other words reduced susceptibility to fading).
The application of MIMO methods to HSPA systems may require different method with regards to calculating or estimating the Signal to Interference and Noise Ratio (SINR), compared with the methods used in conventional HSPA. In a MIMO implementation data is typically split into at least two streams and the data symbols are pre-coded with the help of pre-coding weights whilst the pilot symbols are transmitted on a separate channel, the Common Pilot Channel (CPICH), without pre-coding. As the CPICH pilot symbols are not pre-coded, it may not be appropriate to use the conventional SINR estimation methods.